Journal Article

PUBDB-2024-01035

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Hydrogen-based direct reduction of combusted iron powder: Deep pre-oxidation, reduction kinetics and microstructural analysis

Choisez, L. (Corresponding author) ; Hemke, K. ; Özgün, Ö. ; Pistidda, C.Extern* ; Jeppesen, H.DESY* ; Raabe, D.Extern* ; Ma, Y.

2024
Elsevier Science Amsterdam [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.actamat.2024.119752  doi:10.3204/PUBDB-2024-01035

Abstract: Iron powder can be a sustainable alternative to fossil fuels in power supply due to its high energy density and abundance. Iron powder releases energy through exothermic oxidation (combustion), and stores back energy through its subsequent hydrogen-based reduction, establishing a circular loop for renewable energy supply. Hydrogen-based direct reduction is also gaining global momentum as possible future backbone technology for sustainable iron and steel production, with the aim to replace blast furnaces. Here, we investigate the microstructural formation mechanisms and reduction kinetics behind hydrogen-based direct reduction of combusted iron powder at moderate temperatures (400–500 °C) using thermogravimetry, ex-situ X-ray diffraction, scanning electron microscopy coupled with energy dispersive spectroscopy and electron backscatter diffraction, as well as in-situ high-energy X-ray diffraction. The influence of pre-oxidation treatment was studied by reducing both as-combusted iron powder (50 % magnetite and 50 % hematite) and the same powder after pre-oxidation (100 % hematite). A gas diffusion-limited reaction was obtained during the in-situ high-energy X-ray diffraction experiment, with successive hematite and magnetite reduction, and a strong increase in reduction kinetics with initial hematite content. Faster reduction kinetics were obtained during the thermogravimetry experiment, with simultaneous hematite and magnetite reduction. In this case, the reduction reaction was limited by a mix of phase boundary and nucleation and growth models, as analyzed by multi-step model fitting methods as well as by microstructural investigation. When not limited by gas diffusion, the pre-oxidation treatment showed almost no influence on the reduction time but a strong effect on the final microstructure of the reduced powder.

Note: Funding: F.R.S.FNRS chargée de recherche mandate (ID 40011141); Walter Benjamin Programme of the Deutsche Forschungsgemeinschaft (project number 468209039); ERC Advanced grant ROC (Grant Agreement No 101054368)

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Contributing Institute(s):

1. Experimentebetreuung PETRA III (FS-PET-D)
2. Helmholtz-Zentrum Hereon (Hereon)
3. FS-Photon Science (FS-PS)
4. DOOR-User (DOOR ; HAS-User)

Research Program(s):

1. 632 - Materials – Quantum, Complex and Functional Materials (POF4-632) (POF4-632)
2. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)
3. FS-Proposal: I-20211077 (I-20211077) (I-20211077)

Experiment(s):

1. PETRA Beamline P02.1 (PETRA III)

Appears in the scientific report 2024

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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